Display screen or portion thereof with a graphical user interface



The sole FIGURE is a front elevational view of the display screen orportion thereof with a graphical user interface in accordance with thenew design. The broken lines showing the display screen or portionthereof and the broken lines showing the remainder of the graphical userinterface are for environmental purposes only and form no part of theclaimed subject matter.

CLAIM The ornamental design for a display screen or a portion thereof with a graphical user interface, as shown and described. 